1. Field of the Invention
The present invention relates to a noise damping device for a rotating body and a disk player, and more particularly, to a noise damping device which has an improved structure so as to dampen noise generated by the flow of ambient air when a rotating body or a disk, disposed in a housing, rotates.
2. Description of the Related Art
In general, in a disk player such as a DVD player, a CD-ROM player, or a hard disk drive, a rotating body such as a hard disk or a compact disk is placed in a housing thereof. While rotating at high speed, such a rotating body generates noise due to fluctuation in the air surrounding the rotating body. Therefore, in the above apparatus, a noise dampening device for damping rotation noise of the rotating body is provided.
FIG. 1 is a partially cut away perspective view schematically illustrating a hard disk drive used as an auxiliary memory device of a computer.
Referring to FIG. 1, a hard disk drive is provided with a housing 10, a hard disk 18 installed in the housing 10 and a noise damping device.
The housing 10 is installed in a computer main body (not shown), and comprises a base frame 12 supporting hard disks 18 and a cover frame 14 attached on the base frame 12 for protecting the hard disks 18.
While the hard disks 18 are rotated by a driving source such as a spindle motor installed in the housing 10, data are written to the hard disks 18 or written data are read from the hard disks 18 by a predetermined data writing/reading means (not shown). In addition, there are several hard disks 18 for increased storage capacity.
The noise damping device is attached to the outer surface of the cover frame 14 by an adhesive such as a bond or a double-sided bonding tape, and comprises a damper member 16 usually manufactured in a thin plate structure using stainless steel. The damper member 16 is specifically designed to mainly damp noise in a predetermined frequency range considering the rotation speed of the hard disks 18. For example, when the hard disks 18 rotate at a rotation speed of about 12 m/s, the damper member 16 is designed to mainly damp noise in the range of around 1,500 Hz corresponding to the rotation speed.
In the hard disk drive having the above structure, when the hard disks 18 are rotated by the spindle motor so as to write data to or read written data from the hard disks 18, as shown in FIG. 2, most of the air within the housing 10 tends to flow in xcex8 and R directions. Here, the air flowing in xcex8 direction is distributed at irregular pressures with respect to R directions, and the air in itself flows irregularly. When the irregular air flow impacts the inner walls of the housing 10, the housing 10 is vibrated by the impact, and consequently, undesirable noise is generated. Further, when the air flowing in the R directions reaches the inner walls of the housing 10, the air flow direction is changed to an r direction and the air is mixed with the air flowing in the xcex8 direction. Therefore, the air flow in the xcex8 direction becomes more irregular, and consequently, the noise is increased. Such noise is damped to some extent by the damper member 16 absorbing the vibration of the housing 10.
However, in the above conventional art, since the damper member 16 for damping noise must be separately attached to the outer surface of the housing 10, there are problems in that the manufacturing cost is high and more assembling operations are required. In addition, when the temperature within a computer main body and/or the housing 10 rises, the bonding force of the adhesive deteriorates due to the heat generated in the computer main body. Further, the damper member 16 can only control a predetermined frequency band. Thus, noise with various frequency bands, when the rotation speed of the hard disks 18 varies, cannot be effectively dampened.
The present invention provides a noise damping device for a rotating body capable of effectively dampening noise generated by the rotating body by modifying the structure of a housing.
Also, the present invention provides a noise damping device for a disk player capable of damping noise generated when a disk rotates by modifying the structure of parts installed in a housing.
Accordingly, to achieve the first objective, there is provided a noise damping device for a rotating body for dampening noise due to the air flow within a housing caused by the rotation of a rotating body, wherein an intaglio and/or cameo pattern of a predetermined shape is formed on inner surfaces of the housing.
Here, it is preferable that the housing includes a base on which the rotating body is placed, and a cover frame assembled to the base for covering the rotating body, and the pattern is formed on the upper surface of the base and the inner surface of the cover frame facing the rotating body.
In addition, it is preferable that the pattern is formed on the inner side surfaces of the housing.
In addition, it is preferable that the pattern has a starting point on the rotation axis of the rotating body, and is composed of a plurality of coaxial circles each having a predetermined width, the distances between neighboring circles are the same, and the coaxial circles have respective widths different from each other.
In addition, it is preferable that the pattern has a starting point on the rotation axis of the rotating body, is composed of a spiral having a predetermined width and is capable of guiding the air flow in radial directions from the starting point.
In addition, it is preferable that the pattern has a starting point on the rotation axis of the rotating body, is composed of radially disposed elements each having a predetermined width and is capable of guiding the air flow in radial directions from the starting point, and each of the radially disposed elements has a curved form.
In addition, it is preferable that the pattern is composed of a plurality of circles having a predetermined width and respective radii different from each other. The circles which touch neighboring circles guide the air flow guided by an inner circle toward an outer circle with respect to the rotation axis of the rotating body.
In addition, it is preferable that the pattern is composed of a plurality of dimples having a predetermined width and depth.
In addition, it is preferable that the device includes a vibration absorbing damper member installed on the outer surface of the housing.
To achieve the second objective, there is provided a noise damping device for a disk player for dampening noise due to the air flow within a housing caused by the rotation of a disk, wherein the device includes a disk tray which is movably installed to carry the disk into or out of the housing and is provided with a cameo and/or intaglio pattern of a predetermined shape formed on the surface of the disk tray facing the disk.
Here, it is preferable that the device further includes a clamping member which is installed within the housing for clamping the disk and is provided with a cameo and/or intaglio pattern of a predetermined shape formed on the surface of the clamping member facing the disk.
In addition, it is preferable that the device includes a noise absorbing member installed at the housing.